Apparatus for rolling strip metal



R. G. BENNEWITZ APPARATUS FOR ROLLING STRIP METAL July 1l, 1944.

Filed Dec. 2, 1940 2 Sheets-Sheet 1 ATTORNEY5 July 1l, 1944. R. G.BENNEwl-rz APPARATUS FOR ROLLING STRIP METAL 2 sheets-smet 2 Filed Dec.2, 1940 a: ...q Y O/ mw* W: w. MM NT. N :Gf 1MM K Q m u p0: R @www u N%M\ wm ma m .@w Kw Nm u@ ww W /m/: ha L@ www wm 1 :2:55:53 .u R f 55m@ATTORNEYS methods and apparatus for cold Patented July 1 1, 19442,353,290 APPARATUS FOR ROLLING STRIP METAL Richard G. Bennewitz, JerseyCity,

Steel Company of to Crucible N. J., assignor America, New

York, N. Y., a corporation of New Jersey Application December 2, 1940,Serial No. 368,125

4 Claims.

This 'invention relates to improvements in drawing and rolling metalrod, wire, narrow strip or like stock having a thickness comparable toits width, and is particularly adapted for the cold drawing and rollingof such stock to form special shapes.

This application is a continuation in part of applicants copendingparent application, Serial No. 350,789, filed August 3, 1940. Whereassaid parent application pertains more particularly to method andapparatus for the cold reduction by rolling of metal strip which isrelatively wide in relation to its thickness, the present invention isconcerned primarily with the cold reduction by combined drawing androlling, of metal rod, wire, narrow strip, or like stock, having athickness comparable to its width, as well as for imparting specialshapes thereto, such as a square, hexagonal, etc., contour.

As brought out in said parent application, apparatus for cold rollingmetal strip has heretofore been devised, in which the strip is pulledbetween a pair of relatively small reducing or working rolls, eachbacked by an anti-frictionally supported backing roll of much largerdiameter, the axes of the four rolls all being in a common plane whichis perpendicular to the direction of movement of the strip, thisconstituting the so-called 4-high construction. This construction,however. is subject to a number of disadvantageous and undesirablefeatures as follows. Owing to the fact that the working rolls arebacked'only in a direction perpendicular to the direction of rolling,but are unbacked or unsupported in the direction of rolling, they aresubject to lateral flexure or bending in this direction due to the pullexerted by the strip, such as is productive of a strip of non-uniformtransverse thickness, and produces riilling at the edges. To minimizethis tendency the working rolls must be made relatively large and thediameter of the backing rolls correspondingly increased to maintaintheir appropriate dimensions in relation to the working rolls. Theselarge working rolls diminish the maximum reduction or bite that can beemployed during rolling, while the combination of large Working andbacking rolls greatly increases the overall dimensions, weight and costof the mill. Moreover, with the 4-high construction, although thebacking rolls maybe provided with anti-friction bearings, such as rollerbearings, this cannot be done with the Working rolls due, for onevreason, to lack of space and also, for the more important reason, thatthe working rolls must be set up tightly in split friction bearings, ofbabbitt or the like, to hold the working rolls rigidly in line asrequired with the backing rolls, and in order to make the requisiteadjustments from time to time during rolling, rto maintain the workingrolls so aligned with the backing rolls. Anti-friction bearings, such asroll or ball bearings, could not be employed for the working .rolls inthe 4-high construction, inasmuch as the play in the bearings thusintroduced would cause misalignment of 'the working and backing rollsand thus produce riillng, buckling and non-uniform thickness of thestrip. The fact that the working rolls must be thus tightly set up insplit friction bearings in the 4-high construction entails the furtherdisadvantage that a steady flow of lubrication is required on the rollnecks in order to prevent over-heating of the bearings and roll necks.Owingto this heated oil splashing on the strip, it is impossible toproduce a strip having a bright lustrous finish.

It is also known to construct cold rolling mills with a pair of workingrolls each of which is backed by a pair of spaced backing rolls havingtheir axes in a plane parallel to the strip and each bearing against theassociated working roll, the so-called cluster construction. In mills ofthis type which have been heretofore devised, however, theworking rollshave been directly driven through drive shafts connected thereto.through wobblers on the like. Owing to the drive thus applied directlyto the workf ing rolls, these rolls must be made relatively heavy tominimize the resulting tendency for lateral deflection thereof, and thebacking rolls must be made correspondingly larger and heavier than wouldotherwise be required in order to preserve the proper relative sizes ofthe Working and backing rolls. Also the workingrolls must be madesufficiently large so that such driving connections can be made thereto.To further minimize [this lateral deflection and displacement of theworking rolls, they must again be tightly set up in split frictionbearings, requiring heavy and continuous lubrication during operation toprevent over-heating, with the resulting disadvantages above noted forthe 4-high construction. Likewise, with this type ofV mill, it isdifficult to roll strip of uniform cross-sectional thickness with a highdegree of Arapidity and with no rifing or buckling of the strip, and forthe same reasons explained in connection with the 4-high construction.

' in, such as In accordance with applicants invention, the clusterarrangement of the working and backing rolls is employed, i. e., each ofa pair of working rolls is backed by a pair of spaced backing rollsbearing against the same, but with this important distinction over theprevious types of cluster mill construction that the Working rolls arenot themselves driven, but are merely cradled between and backed bytheir associated backing rolls. The stock being rolled, is propelledentirely by tension applied thereto, i. e., the material being rolled ispulled through the mill. Owing to the fact that eachworking roll iscradled between and backed by a pair of backing rolls, and thusautomatically maintained in proper alignment there, and owing to thefurther fact that no drive is applied to the working rolls, no bearings,other than loose thrust bearings, are required for the working rolls.The working rolls are thus supported exclusively by the backing rolls inrolling contact therewith. Accordingly, the working rolls are subject tono overheating or frictional drag, such as is produced in priorconstructions due to the friction bearings required. Also since, asstated, each working roll is cradled and automatically aligned between apair of backing rolls in contrast to the vertical roll arrangement ofthe 4-high construction, and since the working rolls are not themselvesdirectly driven, as in the case of the prior cluster mill constructions,the working rolls of applicants construction are not subject to fiexurein the direction of rolling, as is the case with prior constructions.The working rolls and their associated backing rolls may accordingly bemade much smaller than in the prior types of 4c-high or cluster mills,thereby greatly reducing the overall dimensions, Weight and cost of themill for any given size of stock to'vbe rolled. The smaller workingrolls which can thus be employed permit of reducing the stock to thedesired dimensions in fewer passes than previously, due to the increasedbite that can be employed effectively. Rolling costs are thus reducedand a superior product obtained.

Further in accordance with applicants construction, the backing rollsare mounted in antifriction bearings, such as roller bearings. Owing tothis fact and the fact that no bearings are required for the workingrolls, the bearing losses for the entire mill are reduced to such apoint that the strip or bar may be rolled exclusively by tension appliedthereto, i. e., by pulling the strip through the mili and without dangerci rupturing the stock. The friction losses are in fact so small thatthe stock can be rapidly reduced at a relatively high rate of speed, forexample as high as i509 feet per minute. Certain modications ofapplicants above mentioned improvements, in forms adapted for coldrolling relatively wide metal strip, are disclosed, as stated, in hiscopending application Serial No. 350,789, filed August'S, 1940, of whichthis application is a 4continuation in part. The present application ismore particularly directed to forms of the invention which are adaptedfor example, to be employed for drawing and rolling special shapes, suchas the conversion of round bars into square, hexagon, etc., shaped rodsor wires, or the reduction in cross-sectional area or" round, square,hexagon, etc., shaped rods, wires, etc., while maintaining their contourunchanged. This may be accomplished in accordance with one aspect of thepresent invention by the use of work rolls having appropriately shapedgrooves there- V notches, etc., or more preferably by the use ofbuilt-up work rollsl consisting oi hardened and ground washers ofappropriate contour.

Cylindrical areas for contacting with the backing rolls may be providedon the work rolls closely adjacent each side of the grooved areas, thusmaintaining the full beneilt of the self-aligning feature and preventingbending of the work rolls despite th'e fact that the built-up characterof the roll with its grooved area tends to substantially weaken it. Ifit were attempted to hold in alignment such a small built-up" groovedwork roll by the use of roll necks and friction bearings, as in the4-high" type of mill, the middle portion of the roll would be free tobend in varying amounts depending on the stock tension and the shape andsize of the grooves, thus making it impossible to roll the stockaccurately' to the desired shape. Also if it were attempted to use theold cluster type of mill with driven workrolls of such a small built-upgrooved type, it will be apparent that the above indicated difllcultieswith that type of mill would be greatly increased and the work rollconstruction would be too Weak to permit accurate rapid rolling of thestock to the desired special shapes.

'I'he present application is also particularly directed to forms of theinvention which are adapted to not only roll the upper and lowersurfaces of the stock, but also to roll concurrently its sides or edgesto the particular shapes desired. That is, the rolling head for rollingthe upper and lower surfaces, may be followed or preceded by anotherrolling head mounted in a position for example, at rightI angles to thefirst, and also having a pair of generally similar work rolls formedwith grooves of desired cross sections, so that the two pairs of workrolls will serve to reduce complementary portions of the outline of thedesired special shape, while the stock is advanced solely by pulling itthrough the two rolling heads in succession. Thus it is possible toproduce round,

square, beveled or other shapes with a cold rolled finish, both on theupper the stock as well as on and lower surfaces of its edges or sidesurfaces. Such rolling operations could not be carried out on the knowntypes of 4-high and cluster mills. Also the improved types of rollingheads embodying the invention are particularly adapted for use as a drawblock through which the stock is pulled.

Various further and more specific objects, features and advantages o theinvention will appear from the detailed description given below, takenin connection with the accompanying drawings forming a part of thisspecification and illustrating merely by way of example certainembodiments of the invention. 'I'he invention consists in such novelfeatures, methods, arrangements and combinations of parts as are shownand described herein.

In the drawings:

Figs. l and 2 are plan and side views, somewhat schematicallyillustrating the manner in which two of the rolling heads, in accordancelwith the invention may be mounted at right angles to each other and inassociation with a winding drum for pulling the stock from an unwindingreel through the heads;

Figs. 3 and 4, are top and end views respectively of one of the rollingheads embodying the invention; l

Figs. 5 and 6 lare vertical sectional views taken substantially alongthe lines 5 5 and 6 6 of Fig. 3; and

Fig. 'l is a view partially in section showing a typical "built-upgrooved work roll constructed in accordance with the invention.

Referring now to Fig. l, a winding drum is shown at I which may be of asuitable known type of construction secured to a foundation as at il andadapted to be power driven through gearing as at I2. This drum may beprovided with clamping means of a suitable known type as at I3 forsecuring the end of the stock 9 to the winding drum. The stock 9 may bepulled by this drum from a reel or pay-out block as at i4, through apair of the rolling heads as indicated at I5 and I6. As shown, each ofthese rolling heads may include a pair of work rolls as at I1, I8 andI1', I8', preferably of the small built-up grooved type above referredto. Each of these work rolls may be backed or cradled by a pair ofbacking rolls asat I9, 20 and I9', 20', or as at 2.I,.22 and 2|', 22.

Since the rolling heads I5 and I6 may be the same or similar inconstruction except for the desired differences in the form of thegrooves for the work rolls, Figs. 3-6 inclusive will serve to illustratethe constructional features of both. Each of these rolling heads may becontained in a box-like frame as at 23 having a base as at 24 adapted tobe bolted to a Ifoundation as at II. The box 23 may contain two pairs ofbearing -housings as at 25, 26 and 21, 28, each of said housings beingcommon to the anti-friction bearings for one end of each of two adjacentbacking rolls as shown. That is, as apparent from Fig. 3, the bearinghousing 25 for example,` serves to carry the upper anti-frictionbearings for the two backing rolls I9, 20, and the bearing housing 21similarly carries the anti-friction bearings for the two backing rollsI9', 20'. Similarly the bearing housings 25 and 28 respectviely carrythe anti-friction bearings for the backing rolls I9, 2U and I9', 20. Thebearing housings 25 and 25 `with the bearings and work rolls associatedtherewith, may be slid into place in the box structure 23 as shown, andremovably secured as by bolts 29. The bearing housings 21, 28 with thebearings and backing rolls I9', 20 in association therewith, are adaptedto be slidably received in the box structure 23 and so as to beadjustable toward or away from the stock 9. To af.- ford suchadjustment, the bearing housings 21, 28 may be backed by a plate member30 adapted to be engaged by set screws as at 3|, carried in a side wallof the box structure 23. The bearing housings 21 and 28 may be also heldin proper spaced relationship at their corners with strips as at 32, 33removably bolted in place as shown and accurately shaped for slidablyengaging the side walls of the box structure 23 so that upon adjustmentsof the positions of the bearing housings, the same will be accuratelyslidable in a direction at right angles to the strip. f

The anti-friction bearings for the backing rolls may all be of the sameor a similar construction such as shown in Fig. 6. As here shown,

for example, the backing roll I9' is formed with short rigid upper andlower necks 34, 35 journaled in anti-friction roller bearings as at 38,31. The necks 34, 35 may extend with a smaller diameter as at 33, 38Vinto anti-friction thrust bearings as at 43, 4I enclosed in bearingrings as at 42, 43.

A pair of bars as at position by screws as shown,

44', 45 may be held in across the top of roll may be readily .built-uphaving a central 'be shaped to correspond to the two comple- .ment. Theside walls of the box structure 23 yif desired therethrough.

while the invention has been` described m de- 42, etc., againstdisplacement vertically from the box structure `while still permittingthe bearing assemblies for the backing rolls I8', 20' to be slidablyadjusted toward and away from the stock.

The work rolls, a typical one of which is shown in Fig. '1, may comprisea stud-like cylindrical center piece as at 46, formed with a ange as at41 near one end and threaded near the other end as at 48 for receiving aclamping nut as at 49. Several disc or washer-like members as at 50forming the built-up construction of the work roll, may be clamped asshown between the flange 41 andnut 49. If for exampleit is desired thatthe stock be rolled with a hexagonal cross section, then a middle discof smaller diameter may be provided as at 5I having an outer cylindricalsurface. 'I'his disc may be flanked by somewhat larger discs 52, 53having a part of their outer surfaces of cylindrical form and partiallybeveled as shown at an appropriate angle. The discs 52, 53 may beflanked by two more discs as at 54, 55 having cylindrical outersurfaces. By using discs of varying diameters and with different formsof peripheral surfaces, in this way it will be apparent that the workgroove of the'desired cross section to correspond to the special shapeof the stock to be rolled, and the grooved area will be flanked by apair of adjacent cylindrical areas for contacting with the backingrolls, so that the work roll will be self-aligning and held accuratelyin position as it rotates, by the backing rolls.' The work rolls of oneof the rolling heads may be thus formed with grooves correspondingrespectively to two quarters of the cross sectional outline desired tobe imparted to the stock, whereas the V*gbvesm of the work rolls of theother rolling head may mentary quarters of such outline. These builtupwork rolls in accordance with this invention are not provided with rollnecks adapted for journaling the rolls, although as shown in Fig. 7, thecentral stud member 46 may be extended somewhat as at 56, 51 merely toprovide means for centering anti-friction thrust bearings as at 58, 58respectively (Fig. 5). That is, the work rolls are free in radialdirections to assume positions determined by the two cradling backingrolls against which the work roll is thrust under pressure of the stockas pulled through the mill in contact with the work roll grooves. Theantifriction bearings as at 58, 59 on the work rolls merely serve toprevent endwise movement ofthe work rolls and to thus retain the groovesof the cooperating pair of work rolls in proper relationship to eachother and to the stock.

The anti-friction thrust bearing assemblies at 58 and 59 may be receivedand held in place within suitably shaped cut-out portions as at 60, 6I,62, 63, of the bearing housings 21, 28, 25, 25 respectiveLv. 'I'hat is,a substantial portion of the side walls of these bearing assemblies, aswall as portions of the outer'faces thereof, may be embraced withinthese cut-out portions so that the work rolls are held against endwisedisplacemay be formed with openings as at 64 (Fig. 4) to permit thestock 8 to be introduced through the rolling head and freely pass backand forth BEST AVAILABLE COPY 4 tail with respect to a particularpreferred example, it will be understood by those skilled in the artafter understanding the invention that various changes and modificationsmay be made without departing from the spirit and scope of theinvention, and it is intended therefore in the appendedclaims to coverallsuch changes and modifications.

What is claimed as new and desired to be secured by Letter' Patent is:

1. In apparatus-.for cold rolling and drawing metal rod and thelike to apredetermined crosssectional shape, a cooperating pair of superposedundriven reducing rolls formed respectively with circumferential groovesof cross sections substantially corresponding to complementary portionsof the outline of said shape, a pair of axially spaced undrivenl andanti-frictionally journaled backing rolls for each of said reducingrolls, each reducing roll being freely cradled between and supported inlfree rolling contact against its associated pair of backing rolls, andmeans for pulling the stock between said pair of reducing rolls inworking engagement with the grooved portions thereof.

2. In apparatus for cold rolling and drawing metal rod and the like to apredetermined crosssectional shape, a cooperating pair of superposedrelatively small reducing rolls, at least oneof which is formed with acircumferential groove of a cross section substantially corresponding toa portion of the outline of said shape, a pair of axially spaced,undriven and anti-frictionally journaled backing rolls for each of saidreducing rolls, each reducing roll being freely cradled between andsupported in. free rolling contact against its associated pair ofbacking rolls, and means for pulling the stock between said reducingrolls.

line of said shape, another and succeeding cooperating pair ofsuperposed undriven relatively small reducing rolls also formed withcircumferential grooves of cross sections substantially corresponding toremaining complementary portions of the outline of said shape, a pair ofundriven anti-frictionally journaled and axially spaced backing rollsfor each of said reducing rolls, each reducing roll being freely cradledbetween and supported in free rolling contact against its associatedpair of backing rolls, and means for pulling the stock between saidpairs of reducing rolls successively in working engagement with thegrooved portions thereof.

4. In apparatus for cold rolling and drawing metal rod and the like to apredetermined cross# sectional shape, a. cooperating pair of superposed,relatively small, undriven reducing rolls, at least one of whichcomprises. a plurality of disc-like members of different diametersretained in faceto-face relationship upon a stud to thereby form acircumferentially grooved Working surface of a cross sectionsubstantially corresponding to portions of the outline of said shape, apair of axially spaced backing rolls for each of said reducing rolls,each reducing roll being freell cradled between and supported in freerolling contact against its associated pair of backing rolls, and meansfor pulling the stock between said reducing rolls.

l RICHARD G. BENNEWITZ.

